EP0084115B1 - Verfahren zur hydrothermalen Kristallzüchtung - Google Patents

Verfahren zur hydrothermalen Kristallzüchtung Download PDF

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Publication number
EP0084115B1
EP0084115B1 EP82111337A EP82111337A EP0084115B1 EP 0084115 B1 EP0084115 B1 EP 0084115B1 EP 82111337 A EP82111337 A EP 82111337A EP 82111337 A EP82111337 A EP 82111337A EP 0084115 B1 EP0084115 B1 EP 0084115B1
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EP
European Patent Office
Prior art keywords
vessel
crystals
nutrient
orthophosphate
berlinite
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP82111337A
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English (en)
French (fr)
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EP0084115A3 (en
EP0084115A2 (de
Inventor
Bruce Huai-Tzu Chai
Ernest Buehler
John James Flynn
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Allied Corp
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Allied Corp
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Priority to AT82111337T priority Critical patent/ATE27312T1/de
Publication of EP0084115A2 publication Critical patent/EP0084115A2/de
Publication of EP0084115A3 publication Critical patent/EP0084115A3/en
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Publication of EP0084115B1 publication Critical patent/EP0084115B1/de
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    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B7/00—Single-crystal growth from solutions using solvents which are liquid at normal temperature, e.g. aqueous solutions
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B25/00—Phosphorus; Compounds thereof
    • C01B25/16—Oxyacids of phosphorus; Salts thereof
    • C01B25/26—Phosphates
    • C01B25/36—Aluminium phosphates
    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
    • C30B29/10—Inorganic compounds or compositions
    • C30B29/14—Phosphates
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T117/00—Single-crystal, oriented-crystal, and epitaxy growth processes; non-coating apparatus therefor
    • Y10T117/10—Apparatus
    • Y10T117/1024—Apparatus for crystallization from liquid or supercritical state
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T117/00—Single-crystal, oriented-crystal, and epitaxy growth processes; non-coating apparatus therefor
    • Y10T117/10—Apparatus
    • Y10T117/1024—Apparatus for crystallization from liquid or supercritical state
    • Y10T117/1096—Apparatus for crystallization from liquid or supercritical state including pressurized crystallization means [e.g., hydrothermal]

Definitions

  • This invention relates to a process for growing single crystals of alpha-aluminum orthophosphate and alpha-gallium orthophosphate.
  • Alpha-aluminum orthophosphate (berlinite) and alpha-gallium orthophosphate (GaP0 4 ) are among several alpha-quartz isomorphs that have for decades been synthesized for research purposes.
  • An attempt to grow large single crystals of berlinite began after World War II, in an effort to find new piezoelectric crystals for frequency control applications. The project ended a few years later, because success was achieved in quartz crystal growth and because quartz was considered superior for the piezoelectric devices known then. Specifically, it was concluded that berlinite had a lower Q and lower coupling coefficient than quartz.
  • tests on both X and Y cuts of berlinite plates, showing a negative frequency drift with increasing temperature indicated that there was little chance of finding a zero temperature cut similar to the AT cut of quartz.
  • seed crystals are suspended near the bottom of a vertical autoclave and nutrient powder is suspended in a basket at the top. Both seed and nutrient are immersed in concentrated phosphoric acid.
  • the temperature is raised slowly from about 150°C over a period of days.
  • a temperature gradient is maintained in the autoclave. In some cases, a gradient is maintained as the temperature is slowly raised.
  • a process is provided for growing crystals of alpha-aluminum orthophosphate or alpha-gallium orthophosphate.
  • the process comprises the steps of
  • This invention provides a process for preparing single crystals of isomorphs of alpha-quartz, namely as berlinite and GaP0 4 .
  • berlinite namely as berlinite and GaP0 4 .
  • the procedure for growing berlinite crystals is described below; except where noted, the preparation of GaP0 4 crystals is identical.
  • a suitable apparatus comprises a substantially cylindrical pressure vessel for containing the materials of the process and means for heating the vessel and maintaining it at a predetermined temperature gradient.
  • the apparatus is described below in some detail, although the process of this invention may be practiced with other apparatuses. Additional detail appears in EP-Al-0057773.
  • the pressure vessel is adapted for holding a mixture of hydrochloric acid and phosphoric acid, in which is immersed, in one chamber, one or more berlinite seed crystals, and, in one or two adjoining chambers, coarse berlinite crystalline powder (or nutrient). (Of course, when GaP0 4 crystals are being grown, the seed and nutrient are of that material.)
  • the vessel walls are preferably transparent to permit observation of the growth process.
  • each seal may comprise an elastomer gasket for mounting between a fluoropolymer plug and the tube.
  • the plug and gasket are preferably resistant to the high temperature and pressure and corrosive environment in the vessel.
  • PTFE @ is a suitable fluoropolymer
  • Viton8 is a suitable gasket material.
  • Each chamber of the vessel is separated from the adjoining chamber(s) by a baffle.
  • the baffle serves to maintain a temperature gradient between the chambers, while, at the same time, permitting liquid to flow between the chambers.
  • the baffle material is desirably thermally insulating and resistant to the corrosive environment and high temperatures in the pressure vessel.
  • berlinite seed crystals are suspended in a chamber of the vessel.
  • the seed crystals are prepared by a process known in the art; for example, the process described by Krauss et al. (Z. Naturaba, 30A, 28 (1975)).
  • Suitable seed crystals prepared by Krauss's method are single crystals at least 5 mm across.
  • a plurality of seed crystals are used, their orientation and positioning chosen to maximize growth rate, minimize crystal defects, and avoid contacting growing crystals with the vessel wall.
  • the seed crystals are suspended from fluoropolymer seed hangers mounted on a frame formed of a corrosion-resistant material.
  • Platinum wire frames having sufficient springiness to push against the vessel walls for support, have been used satisfactorily.
  • Preparation of the coarse berlinite powder, or nutrient, that is used in the present process is disclosed in EP-A1-0057814.
  • the preferred particle size for the nutrient is 20-60 mesh (sieve opening 250-850 g m).
  • the nutrient is introduced into one or more chambers adjoining that which holds the seed crystals.
  • the nutrient is contained in a pervious enclosure that permits liquid flow- through while retaining all but the smallest nutrient particles. It is important that small particles of nutrient do not make their way to a growing crystal and become incorporated in it. Orienting the vessel horizontally reduces that possibility.
  • Hydrochloric and phosphoric acids are introduced into the vessel in an amount to submerge the nutrient and seed crystals.
  • Initial HCI molarity is 3-4 M.
  • Reagent grade HCI is suitable.
  • Electronic grade 85% H 3 P0 4 is commercially available and suitable.
  • the initial H 3 PO 4 molarity is 2-3 M (when GaP0 4 is being prepared, higher H 3 P0 4 molarity, 3-10 M, is employed).
  • the sum of HCI and H 3 P0 4 molarities is preferably about 6-7 (about 8 when GaP0 4 is being prepared), with HCI molarity slightly higher.
  • a mixture of 4 M HCI and 2 M H 3 P0 4 yielded the best results.
  • the heating means may be any of several known in the art.
  • a cylindrical furnace having two independently-controlled resistance heating zones is suitable for achieving the elevated temperature and temperature gradient in the vessel.
  • the temperatures are measured exterior to the vessel, for example using thermocouples, and provide an adequate approximation to the interior temperatures. Temperatures are controlled at the centers of the chambers and may vary by about ⁇ 3°C within each chamber. Conventional controllers capable of maintaining control temperatures within about ⁇ 1°C of the desired temperatures may be used. If the vessel has three chambers, a three-zone furnace is necessary. The vessel is heated to achieve a seed crystal temperature from 135°C to 210°C, with about 170°C preferred.
  • a higher temperature range about 170°-210°C, is preferred for GaP0 4 crystal growth, with about 185°C most preferred.
  • a gradient is established, so that the nutrient is at a temperature 5°C to 30°C lower than that of the seed crystals, preferably about 10°C lower.
  • the nutrient should remain above 130°C, where berlinite undergoes a phase change and the solution chemistry is changed. If the temperature of a growing crystal is too high, excessive nucleation takes place. If the temperature gradient is too large, excessive nucleation also takes place, and, furthermore the solution boils in the regions of the growing crystals. If the temperature is too low, growth is very slow.
  • the vessel is preferably oriented horizontally and fluid in the vessel is continually flowed between the chambers. This is conveniently accomplished by rocking the vessel about a horizontal axis normal to its cylinder axis. The rocking action is accomplished by methods well known in the art, such as a motor drive. Each end of the vessel may be raised and lowered at regular intervals of 6 to 1800 seconds, with the preferred interval range being 10 to 30 seconds. As the vessel is rocked, preferably the nutrient and growing crystals remain submerged.
  • This goal is achieved by using the maximum feasible fill, as discussed above; by not mounting seed crystals or positioning nutrient near the top and ends of the vessel; and by limiting the rocking so that the raised end of the vessel preferably makes with the horizontal an angle of less than 45°, more preferably less than 10°.
  • the berlinite seed crystals grow in the solution when the temperature and temperature gradient are within the appropriate range. After about two weeks, the crystal attains a usable size; however, larger crystals are preferred, requiring a growth period of at least about a month. Growth is stopped when the crystals reach the desired size, or before that if the crystals are coming into contact with the walls or if the nutrient is nearly depleted. Growth should not continue until the nutrient is depleted, since then the crystals go into solution.
  • the vessel is cooled rapidly, for example by spraying the vessel with water, until the pressure is reduced to a value at which the vessel may be opened safely.
  • the vessel may be opened after the temperature is below 100°C; however, for convenience, the temperature may be further reduced to near ambient temperature.
  • a water spray accomplishes cooling in about 10-15 minutes, after which the crystals can be removed from the solution. If more rapid cooling is attempted, there is a danger that the crystals might crack. After recovering them from the solution, crystals grown by the present process are cut into wafers for SAW devices, using conventional slicing machines.
  • An alternative method for recovering the crystals after growth is complete involves a second (or syringe) vessel.
  • the syringe vessel includes means for pumping solution into and out of the pressure vessel, for example a piston mounted in the syringe vessel and one or more highpressure, corrosion-resistant valves to control flow between the vessels.
  • the syringe vessel is joined to the pressure vessel and hot solution is transferred to the syringe vessel. Thereafter, the crystals in the pressure vessel may be cooled slowly to avoid cracking, since they can no longer go into solution. If two valves are used between the vessels, then one syringe vessel can serve several pressure vessels.
  • the syringe vessel can also be used to prevent dissolution of the seed crystal as the system is warmed at the beginning of the process.
  • the acid is heated in the syringe vessel as the nutrient and seeds are heated in the pressure vessel. When the desired temperatures are achieved, the hot acid is transferred from the syringe vessel to the pressure vessel.
  • the temperatures were maintained and the vessel rocked with a period of 10 s/cycle. At the extremes of the rocking, the long dimension of the vessel made an angle of 5° with the horizontal. After 42 days, a water spray cooled the vessel to near ambient temperature in less than 15 minutes, and the crystals were recovered from the solution. Originally about 1 mm thick, the crystals had grown at a rate of 0.107 mm/side/day on the X-plates and 0.102 mm/side/day on the Y-plates.. Heavy nucleation had formed on the vessel walls and had badly damaged the crystal surfaces.
  • Example 1 The apparatus and process of Example 1 were used, exceptthatthe starting solution was 3 M HCI, the seed crystal temperature 169°C, nutrient temperature 148°C, and growth time 29 days. Growth rates (mm/side/day) were: basal: 0.141; X-plate: 0.043; Y-plate: 0.015; (1011 plate: 0.023.Therewas some nucleation atthetop of the vessel and crystal quality was poor.
  • Example 1 The apparatus and process of Example 1 were used, except that the starting solution was a mixture of 3.7 M H 3 P0 4 and 3 M HCI, seed crystal temperature 170°C, nutrient temperature 152°C, and growth time 43 days. Twenty-five basal plates grew at an average rate of 0.227 mm/side/day. Heavy, uniform nucleation took place at the bottom of the vessel. Crystals showed crevices and channels, which would impair their performance in a SAW device.
  • Example 1 The apparatus and process of Example 1 were used, except that the starting solution was a mixture of 2 M H 3 P0 4 and 4 M HCI, seed crystal temperature 170°C, nutrient temperature 154°C, and growth time 28 days. Twenty-five basal plates grew at an average rate of 0.322 mm/side/day. Moderately heavy, uniform nucleation took place at the bottom of the vessel. Crystal quality was excellent.
  • Example 1 The apparatus and process of Example 1 were used, except that the starting solution was a mixture of 2 M H 3 P0 4 and 4 M HCI, seed crystal temperature was 170°C, nutrient temperature 160°C, and growth time 35 days. Twenty-eight basal plates grew at an average rate of 0.194 mm/ side/day. Very light nucleation took place at the bottom of the vessel. Crystal quality was excellent.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Crystals, And After-Treatments Of Crystals (AREA)

Claims (8)

1. Verfahren zur Züchtung von Kristallen eines Metallorthophosphates, das unter alpha-Aluminiumorthophosphat und alpha-Galliumorthophosphat ausgewählt ist, mit den Stufen, bei denen man
a) einen Keimkristall des Metallorthophosphates in einer ersten Kammer eines Druckbehälters aufhängt, wobei diese erste Kammer von wenigstens einer weiteren Kammer mit einer Trennwand, durch die Fließmittel fließen kann, abgeteilt ist,
b) in die wenigstens eine zusätzliche Kammer des Behälters eine Menge von Nährkristallen des Metallorthophosphates einführt,
c) in den Behälter ein Gemisch von Chlorwasserstoffsäure mit einer Molarität von 3 bis 4 M und Phosphorsäure mit einer Molarität von 2 bis 3 M, wenn alpha-Aluminiumorthophosphat hergestellt werden soll, und 3 bis 10 M, wenn alpha-Galliumorthophosphat hergestellt werden soll, in einer Menge, in der die Nährkristalle. und Keimkristalle untertauchen, einführt,
d) den Behälter dicht verschließt,
e) den Inhalt des Behälters so erhitzt, daß man eine Keimkristalltemperatur von 135 °C bis 210 °C und eine Nährkristalltemperatur 5°C bis 30 °C niedriger, aber oberhalb 130 °C bekommt,
f) die Temperaturen in dem Behälter aufrechterhält, wobei der Keimkristall auf einer Säurelösung des Metallorthophosphat wächst, und
g) das Kristallprodukt gewinnt.
2. Verfahren nach Anspruch 1, bei dem der Behälter im wesentlichen horizontal ausgerichtet ist und Fließmittel in dem Behälter kontinuierlich zwischen den Kammern fließt.
3. Verfahren nach Anspruch 2, bei dem das Fließmittel zwischen den Kammern fließt, indem man ein Ende des Behälters in regelmäßigen Abständen von 6 bis 1800 sec anhebt und senkt.
4. Verfahren nach Anspruch 1,2 oder 3, bei dem das Metallorthophosphat alpha-Aluminiumorthophosphat ist und die Summe von Chlorwasserstoffsäure und Phosphorsäure Molaritäten von 6 bis 7 M hat.
5. Verfahren nach Anspruch 1, oder 3, bei dem das Metallorthophosphat alpha-Galliumorthophosphat ist und die Summe von Chlorwasserstoffsäure und Phosphorsäure Molaritäten von etwa 8 hat.
6. Verfahren nach einem der vorausgehenden Ansprüche, bei dem die Mengen an Säure, Nährkristall und Keimkristall so ausgewählt sind, daß sie weniger als 85 % des Volumens des Behälters ausfüllen.
7. Verfahren nach einem der vorausgehenden Ansprüche, bei dem die Stufen c) und d) nach der Stufe e) und vor der Stufe f) durchgeführt werden.
8. Verfahren nach einem der vorausgehenden Ansprüche mit der zusätzlichen Stufe einer Entfernung der Lösung, bevor das Kristallprodukt gewonnen wird.
EP82111337A 1982-01-06 1982-12-07 Verfahren zur hydrothermalen Kristallzüchtung Expired EP0084115B1 (de)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT82111337T ATE27312T1 (de) 1982-01-06 1982-12-07 Verfahren zur hydrothermalen kristallzuechtung.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US06/337,231 US4481069A (en) 1981-01-30 1982-01-06 Hydrothermal crystal growing process
US337231 1989-04-12

Publications (3)

Publication Number Publication Date
EP0084115A2 EP0084115A2 (de) 1983-07-27
EP0084115A3 EP0084115A3 (en) 1985-05-15
EP0084115B1 true EP0084115B1 (de) 1987-05-20

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EP82111337A Expired EP0084115B1 (de) 1982-01-06 1982-12-07 Verfahren zur hydrothermalen Kristallzüchtung

Country Status (6)

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US (1) US4481069A (de)
EP (1) EP0084115B1 (de)
JP (1) JPS58125694A (de)
AT (1) ATE27312T1 (de)
CA (1) CA1212600A (de)
DE (1) DE3276378D1 (de)

Families Citing this family (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2559166B1 (fr) * 1984-02-08 1986-06-13 Centre Nat Rech Scient Procede de croissance de cristaux d'arseniate d'aluminium
FR2559165B1 (fr) * 1984-02-08 1993-01-29 Centre Nat Rech Scient Procede de croissance de cristaux de compose a solubilite retrograde et dispositif pour sa mise en oeuvre
FR2595344B1 (fr) * 1986-03-04 1988-06-24 Centre Nat Rech Scient Procede de preparation de cristaux de berlinite a haut coefficient de surtension
AT395439B (de) * 1987-09-04 1992-12-28 Avl Verbrennungskraft Messtech Verfahren zum zuechten von kristallen und vorrichtung zur durchfuehrung des verfahrens
US4927614A (en) * 1988-02-19 1990-05-22 The Dow Chemical Company Process for growing berlinite crystals
AT398255B (de) * 1992-09-04 1994-11-25 Avl Verbrennungskraft Messtech Hydrothermalzuchtverfahren zum züchten von grossen kristallen oder kristallschichten aus einem metallorthophosphat unter verwendung einer keimplatte
AT401837B (de) * 1993-03-04 1996-12-27 Avl Verbrennungskraft Messtech Piezoelektrisches kristallelement
US6767520B2 (en) * 2001-08-22 2004-07-27 Hosokawa Bepex Corporation Cooling system for polymer processing
JP4249502B2 (ja) * 2003-02-04 2009-04-02 日本電波工業株式会社 圧電結晶材料及び圧電振動子
JP4276627B2 (ja) * 2005-01-12 2009-06-10 ソルボサーマル結晶成長技術研究組合 単結晶育成用圧力容器およびその製造方法
US8236102B1 (en) * 2008-01-30 2012-08-07 Solid State Scientific Corporation Hydrothermal methods of fabricating trivalent-metal-ion-doped sapphire crystals
JP6118593B2 (ja) * 2013-03-12 2017-04-19 日立造船株式会社 両端開閉自在な耐圧反応器

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2675303A (en) * 1950-04-11 1954-04-13 Clevite Corp Method and apparatus for growing single crystals of quartz
US4247358A (en) * 1979-06-08 1981-01-27 The United States Of America As Represented By The Secretary Of The Army Method of growing single crystals of alpha aluminum phosphate
US4300979A (en) * 1980-11-03 1981-11-17 Bell Telephone Laboratories, Incorporated Growth of AlPO4 crystals
US4382840A (en) * 1981-01-30 1983-05-10 Allied Corporation Hydrothermal crystal growing process and apparatus
US4324773A (en) * 1981-01-30 1982-04-13 Allied Corporation Hydrothermal process and apparatus for synthesizing crystalline powders

Also Published As

Publication number Publication date
JPS58125694A (ja) 1983-07-26
DE3276378D1 (en) 1987-06-25
EP0084115A3 (en) 1985-05-15
US4481069A (en) 1984-11-06
CA1212600A (en) 1986-10-14
EP0084115A2 (de) 1983-07-27
ATE27312T1 (de) 1987-06-15

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